1. Field of the Invention
This invention relates to a process for the production of reformer feed and heating oil or diesel oil from coal by means of liquid-phase hydrogenation and subsequent catalytic gas-phase hydrogenation.
2. Discussion of the Background
DE-PS No. 900 214 describes a process for removing extraneous gases from the circulation gas of a catalytic high-pressure hydrogenation process. In this process, the liquid reaction product of the gas phase reactor, without passing through special scrubbing equipment, is directly used as a scrubbing liquid for the circulating gas of the liquid phase system which has been contaminated by gaseous hydrocarbons, nitrogen and carbon monoxide. The liquid and gas-phase circuits are connected at the inlet and outlet sides of a circulation pump system and all of the hydrogen is introduced either into common circulation or into the gas-phase zone. In the latter case, the difference between the total gas requirement of the gas-phase zone and the added hydrogen, is removed from the outlet side of the common circulation system and is thus cleansed of impurities in the gas-phase.
This process certainly alleviates the requirement for an additional scrubbing system for the removal of impurities from the circulating gas. However, because of the presence of portions of the circulating hydrogen gas from the liquid-phase hydrogenation, optimal refining hydrogenation selectivity cannot be achieved during the gas phase hydrogenation stage. This necessitates using very high hydrogen pressures which results in greater hydrogen consumption.
Accordingly, there exists a strongly felt need for a better process for the production of reformer feed and heating oil or diesel oil from coal. Such a process should have high refining hydrogenation selectivity, should be run with lower operating pressures and should minimize the consumption of hydrogen.